Improvement in tripods for rock-drills



JAMES B. JOHNSON, OF BOSTON, MASSACHUSETTS, ASSIGNOR OF ONE-HALF HIS RIGHT TO EDWARD G. HlGrHT AND EDWARD F. LITTLEFIELD, OF

SAME PLAGE.

IMPROVEMENT IN TRiPODS FOR ROCK-DRILLS.

Speciiication forming part of Letters Patent No. lQ, dated January 30, 1877 application liled July 24, 1876.

To all 'whom it may concern:

Beit known that l, JAMES BROWN JOHN- SON, of Boston, in the county of Suffolk and State ot' Massachusetts, have invented certain new and useful lmprovements in Adjustable Tripods for Rock-Drills; and l do hereby de clare that the following is a full, clear, and exact description thereof, which willenable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification. A

My invention relates to improvements in tripods and clamps for rock-drills, by which the rock-drill cylinder can be adjusted and secured in any desirable position; and my invention consists of` a clamp surrounding the body of the rock-drill cylinder, and provided with two projecting ears, through which a bolt or hinge-pin is inserted, passing through the upper end of one or more of the legs that constitute the tripod, which upper end is provided with cogs or teeth fitting into a pinion that is adjustable as to position between the ears ofthe clamp, by means of a set-screw that passes through the pinion and the clamp-ears, and is secured by a nut on the outside ofthe clamp. The adjustable pinion is made tapering in one ot' its outer ends, that fits in a corresponding taper in the ear of the clamp. The hinge-pin, passing through the upper end of the legs of the tripod, is also provided with a nut on the outside of the ear of the clamp, by which the tripod is still more firmly secured in place after being properly adjusted. If one legis to be attached to the clamp only I use only one pinion; but if two legs are to be' secured to one and the same clamp, I employ two independent pinions, loosely movable around the same bolt,sc that each leg can be adjusted independent of the other in the same clamp. Each leg in the tripod is made hollow, to receive the lower end or ground point, which is secured and adjusted to the upper part of theleg by means of a nut having a tapering recess in its interior, and provided with a flange, on which the weights a cross-section on the line O D, also shown in Fig. l, and Fig. 4 represents a cross section on the line E F, also shown in Fig. l.

Similar letters refer to similar parts wherever` they occur on the different parts ot' the drawings.

a represents the outer smooth cylinder of a roclcdrill, and b b represent the clamps that encompass the said cylinder, and are each provided with a pair ot' ears or projections, c c, between which the upper ends of the hollow legs d d d are hinged by means ot the pins e e', provided with nuts ff on the outside ot' the ears or projectionsc c, as shown. "lhe upper ends of each oi the hollow legs d CZ d is provided with a cog-segment, g gg, as shown, that gears into each ot' the pinions It h h-, which pinions are loosely adjustable on the pins'or bolts 'i t, provided on one end with a head, and on the other end with a fasteningnut, 7c k. One end ot' each of the pinions h h It is made with a taper, l Z t', resting in a corresponding taper in the ears or projections c c, by which the said pinions are firmly secured to the clamp-ears when the nuts 7c k are screwed up tightly against the outside of' the ears c c.

It will be seen that two objects are accomplished by means of the` screw-bolts 't' i', pinions h h It', and segments g g g', namelythe clamps are secured `firmly to the cylinder a at any desired place, atthe same time as the legs are secured rmly in any desired position in relation to the clamps b b and the cylinder a.

On the-drawings, one of the clamps is shown is'immaterial, as the one is only a duplicate ofthe other, and I may, if so desired, employ more than two clamps, each havingA one or more legs secured thereto, without departingQ from the spirit of my invention.

Each of the legs is made hollow, as shown, and provided in its lower end with a screwthreaded tapering split end, mm, around which is screwed a nut, n, having a corresponding inner taper, and provided with an annular ange, u', in its upper end, on which the weights o are supported, for the purpose of steadying the drill-cylinder a during the operation of the drill. The split tapering end of the hollow leg is shown in Fig. 4:.

The object of the said split tapering end of the hollow leg and its nut is to adjust and secure the central ground point of bar p firmly in position in relation to the hollow leg; and this is accomplished by means of' the nut n crowding the tapering split ends of the hollow leg firmly around the central bar 19 when the said nut is tightened up properly.

Having thus fully described the nature, construction, and operation of my invention, I wish to secure by Letters Patent, and claim- 1. In combination with` the plain cylinder a, one or more clamps b b, provided with one or more tapering pinions, h la. h', tighteningboltsvl i', and hollow legs d d d', with their upper segments g y g and hinge-pins e e', as and for the purpose set forth.

2. In combination with the hollow leg d d' d' and its lower taper, of the flanged nut n and its inner taper, and the central adjustable bar p, substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my oivn invention I have affixed my signature in presence of two Witnesses. I

JAMES BROWN JOHNSON.

Witnesses ALBAN ANDRN, HENRY GHADBOURN. 

